It is sealed, Falconnier-style, despite what it looks like in the first picture (where it does appears to have a hole). Top-row is an interesting idea, but it's strange it has a flat back and a... <time passes>... hmm, idea: these look like they would fit together nicely, if you lined them alternating back and front, know what I mean? It wouldn't work to have them all the same direction, not with the angled sides. Top course for a Falconnier wall? They are unmarked, so I assume they are not Falconnier. A competitor? He did patent the idea, in Germany, the U.S., etc.

I like the idea of back and front, but I doubt if Falconnier would have designed it like that. Why not in one piece? He did it with another design of his (see picture). But it does look very much like a brique Falconnier, I agree.

Here's the same picture from the auction, just embedded. [Wonder what the rights status of this image are? I'd like to use it on my forthcoming Falconnier page]:

Half-bricks are much rarer than full bricks since they were only needed for the top and bottom courses. Find me one and I will exchange it for its own weight in Larks' Tongues, Hummingbird Wings, Butterfly Sneezes, Chicken Lips, Bottled Ghosts, whatever you want!

I had an idea about the brown brick which started this thread: the shape reminds me of pre-cast concrete blocks used to make retaining walls. They are meant to be arranged in curves, hence the angled sides. Using a brick with a [isosceles] trapezoidal section would be better for making a curved wall than the normal brick.

Which doesn't explain the fairly unattractive brown color. The only 'colored' one I've seen so far ('colored' defined as not clear, not aqua) has been a very nice emerald green, something which would be agreeable in a wall (all green? just the occasional accent?). But a bottle-brown wall, hmm.

The seller wanted a couple hundred bucks for the brown thing, which I wasn't inclined to risk, what with having recently lost > $500 on what turn out to be an irradiated insulator. But it sure seems like a glass brick!

Your glass was on my mind the whole weekend. I had the feeling that I had seen something like it before, not made of glass but of ceramics, but with the same form. It looks like some sort of rose window when you put six of them together and reminds me of a clock in a railway station. You cannot compare it of course. I’ll send you a photo created of your brick by mail, because I cannot upload a photo on this board.